<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>登录</title>
     <!-- 可选的 Bootstrap 主题文件（一般不用引入） -->
     <link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/bootstrap@4.6.0/dist/css/bootstrap.min.css" 
    integrity="sha384-B0vP5xmATw1+K9KRQjQERJvTumQW0nPEzvF6L/Z6nronJ3oUOFUFpCjEUQouq2+l" crossorigin="anonymous">
    <style>
        .formLogin{
            width: 350px;
            height: 350px;
            background-color: green;
            padding: 30px 30px;
            color:#fff;
            position: absolute;
            top: 0;
            left: 0;
            right: 0;
            bottom: 0;
            margin: auto;
        }
    </style>
</head>
<body>
    <div class="login" style="width:100%;height:100vh;">
        <div class="formLogin">
            <h1 style="text-align:center;">用户登录</h1>   
            <form action="login.php" style="line-height: 15px;">
                <div class="form-group">
                    <label>账号：</label>
                    <input type="text" name="username" class="form-control">
                </div>
                <div class="form-group">
                    <label>密码：</label>
                    <input type="text" name="password" class="form-control">
                </div>
                <button type="submit" style="width:100%;text-align:center;" class="btn btn-primary">添加学生信息</button>
            </form>
        </div>
    </div>
</body>
</html>